I like the big 30's and the big 338's for big animals. I have no gripes with the 300B, with the exception that sometimes a factory gun shoots well and sometimes they don't.
This is mostly due to the long throat. A buddy a 300B that he had a gunsmith accurize when it was new, I think he re cut the chamber with a shorter throat. That gun was very accurate with hand loads. One of his favorites was a 190 Berger. I am more partial to the 300 RUM though and there a lots of quality guns chambered in the 300 RUM and any gun shop could order you the ammo you want. I have one friend that shoots factory ammo from his 300 RUM and he shoots 180 gr swift scirroco's, not sure if remington loads these anymore, but his wife shot a dandy 6 point bull with this gun at 986 yards and had never shot his gun before! Most of my friends that shoot the 300 RUM shoot 215 Bergers and run them around 3050 fps. On my last 300 RUM, I shot mostly 180 gr accubonds and it was a hammer! When my barrel gave up, I built another 338 RUM still my favorite for big animals. When the animals are big, the 338 really shines.